古英語のpocket, bag, sackから、原語ゲルマン語の*puk, 膨らむ, 膨らむ, PIE *beuから、語源的にはpoach, pouch.-etと同じ。すなわち、ポーチ、派生語義のポケット、お金、資金など。
The "pocket veto" can operate only in the case of bills sent to the President within ten days of Congressional adjournment. If he retain such a bill (figuratively, in his pocket) neither giving it his sanction by signing it, nor withholding his sanction in returning it to Congress, the bill is defeated. The President is not bound to give reasons for defeating a bill by a pocket veto which he has not had at least ten days to consider. In a regular veto he is bound to give such reasons. [James Albert Woodburn, "The American Republic and its Government," Putnam's, 1903]